The present invention relates to an unencapsulated solid-state electrolytic capacitor and a method for manufacturing the same. More particularly the present invention relates to a method of assembling a thin unencapsulated solid electrolytic capacitor by connecting a planar anode terminal to an anode lead-out wire.
In general, a solid electrolytic capacitor element of the present invention includes an anode body formed of compressed particles of a film-forming metal such as tantalum, a dielectric film layer formed on the anode body, a semiconductor layer formed on the dielectric film, and a cathode layer formed on the semiconductor layer. The capacitor element has an anode lead-out wire embedded into or welded onto the anode body. Since the lead-out wire is made of a film-forming metal such as tantalum, solderable metal should be welded to the anode lead-out wire to serve as a anode terminal. To be used as as unencapsulated solid electrolytic capacitor, or chip capacitor, the outer surface of the capacitor element is used as a cathode terminal, thereby eliminating both a cathode lead wire and the need for encapsulation. Thus high volumetric efficiency is attained. In order to meet a demand for low profile on a circuit board, both the capacitor element and the anode terminal should be made in planar shape, thereby forming thin chip capacitors. To obtain such thin chip capacitors economically, the planar anode terminal should be so connected to the anode lead-out wire as to enhance the opportunities for mass production.